Summary of "A Level Chemistry Revision "Dative Covalent Bonding"."

Summary of “A Level Chemistry Revision - Dative Covalent Bonding”

Main Ideas and Concepts

Definition of Dative Covalent Bond (Coordinate Bond): A dative covalent bond occurs when one atom donates a lone pair of electrons to another atom that is electron deficient, forming a covalent bond where both electrons come from the same atom.

Example with Ammonia (NH₃): - Nitrogen in ammonia has five outer electrons and forms three covalent bonds with hydrogen atoms. - Nitrogen retains a lone pair of electrons. - This lone pair can be used to form a dative covalent bond with a hydrogen ion (H⁺), which has no electrons to contribute. - The result is the ammonium ion (NH₄⁺), where the nitrogen donates its lone pair to bond with H⁺.

Representation of Dative Bonds: - In displayed formulas, dative bonds are shown with an arrow. - The arrow points away from the atom donating the lone pair.

Important Points About Dative Bonds: 1. The acceptor atom must be electron deficient (have available orbitals for electrons). 2. Dative covalent bonds are chemically identical to normal covalent bonds in terms of bond length and bond enthalpy (strength).

Another Example – Ammonia and Boron Trifluoride (BF₃): - Boron in BF₃ has only six electrons in its outer shell, making it electron deficient. - Nitrogen donates its lone pair to form a dative covalent bond with boron.

Upcoming Topic: The next video will cover molecular shapes.

Methodology / Key Points for Understanding or Identifying Dative Covalent Bonds

Identify atoms with lone pairs of electrons (donor atom).
Identify atoms that are electron deficient (acceptor atom).
When the donor atom shares its lone pair to form a bond with the acceptor, this bond is a dative covalent bond.
Represent the bond with an arrow pointing from donor to acceptor in structural formulas.
Recognize that dative bonds are equivalent in strength and length to normal covalent bonds.

Speakers / Sources Featured

The video features a single presenter (unnamed) providing the explanation and examples.
Visual aids include molecular diagrams of ammonia, ammonium ion, and boron trifluoride.